This is one of those frustratingly difficult games that are simple, yet so difficult you will hardly score into double figures for the first few times you play.

A prisoner is trapped in a cage in a dungeon and you can help him escape. He is initially in a cage and pressing the screen causes the walls to stretch and move. This breaks the cage and the prisoner falls down a very deep shaft.

There are obstacles that will kill him and end the turn, and they must be avoided. Tap the screen and the walls stretch and bounce the prisoner around.

It sounds weird and is hard to explain, but it is vaguely reminiscent of pinball where you control the flippers. Tap the screen and you can flip the guy left or right off the walls, and even back up the screen a little. You can bounce him around to collect the bonuses and avoid the killer traps.

It is difficult, it is frustrating, and you will die a lot, but it is also a lot of fun. It is ad supported, but in-app purchases ($0.99 minimum), remove them.

Rings is a puzzle game that is loosely based on those match three in a row type of games. Line up three objects and they disappear in a puff of smoke.

In this variation there is a grid of nine dots. These are places where you can put coloured rings. Rings are provided three at a time and they must be placed in the grid.

Line up three rings of the same colour and they disappear. The game ends when the grid is full and there is nowhere left to place a ring.

That is basically it, but there is a nice twist and the rings come in several different sizes - very small, small, medium and large. They all fit one on top of the other, so you can put a large green ring outside a small red ring, for example.

This simple feature makes the game much more complex as you not only have to pick the best place for rings, you can also stack them. There is a bonus and a complete stack of the same colour makes them all disappear too.

Rings is a very simple game, but it is addictive and it makes you think, as you try to work out the best strategy. It’s $1.99 to remove the (rarely seen) ads.

Imagine racing a car along the top of the Great Wall of China and you will have a good idea of that this game is about. The aim is to drive your car as fast as possible along a narrow row with a sheer drop to oblivion on either side. It is one scary ride!

The controls are very simple and you don’t even need to steer, even though the road has bends and is rarely straight for very long. The only controls you have are an accelerator and a brake, and these are activated by your thumbs at each side of the screen.

You basically just have to make sure you are not going too fast to take a bend. Get the speed just right and the car swerves around the bend, but get it wrong and you could hit rocks or trees at either side of the road, or where there is a gap, you could drive off the road completely.

The car picks up damage for everything you hit and this slows you down. You also have limited fuel, although it seems to work more like a time limit. Trying to drive slowly and carefully means you just run out of fuel, so it is best to be heavy on the accelerator and get to the next checkpoint where there is extra fuel as fast as possible.

There are car upgrades and in-app purchases. It is a great game that is fast and addictive fun.